J.X. Fang

Exploring the feasibility of a separated function RFQ with mini-vane structure

The accelerating field in the conventional RFQ is originated by the surface modulation of the quadruple electrodes. However, the axial accelerating field generated in this way is quite limited. To enhance the energy gain as well as the focusing power, a post-RFQ accelerating structure called separated function RFQ (SFRFQ) was proposed (Progr. Nat. Sci. 12(1) (2002) 23), and its feasibility has been explored (Chin. Phys. 51(6) (2002)). The RF accelerating field in the SFRFQ structure mainly occurs at gaps between periodical cells, while the electrical quadruple field inside the cells provides the transverse focusing. It turns out that the overall performance can be improved considerably, comparing with that of conventional RFQ. The preliminary results of calculation and model measurements are presented and discussed in the paper.

Simulation Study on 104 MHz Radio Frequency Quadrupole Accelerator

An electrical model of the 104 MHz radio frequency quadrupole (RFQ) accelerator at Peking University is introduced for RF design, based on which every crucial geometrical parameter is swept and selected carefully to improve the RF properties of the RFQ such as the intrinsic quality factor and shunt impedance for reducing its power consumption. Moreover, flatness tuning of the inter-electrodes voltage is investigated in principle. Also, a magnetic coupling loop is designed for power feeding of the RFQ cavity from transmitter. Relevant numerical simulations are performed using 3D electromagnetic field program CST Microwave Studio (MWS).